Electrochemical Sources of Power: Fuel Cells
It is easy, if we forego sophistication, to explain how a fuel cell works. Let us look at Fig. 5.1. The fuel (let us exemplify using hydrogen) enters and is impelled into contact with one electrode in solution. It dissociates, and the resulting hydrogen atoms adsorb upon the electrode. They then give up their electrons to the metal (this is the fundamental electrochemical act of creating electricity), and these electrons then flow around the circuit, through a load, until they reach the other electrode. Here, they transfer to oxygen, which then, along with some protons from the solution, undergoes successive reactions, until water is formed. The overall fuel cell reaction involves oxidation of the fuel and reduction of oxygen occurring on separate electrodes. The stream of electrons is taken from the hydrogen reaction sites to the other electrode to react with oxygen through an outside load where this current is used to produce useful work (e.g., by passing through the armature of a motor).
KeywordsFuel Cell Internal Combustion Engine Heat Engine Fuel Cell System Conventional Power Plant
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